Zyto lathe problem

Dear All,

After 60 years I've taken up metal lathe work again and acquired a 3.75" Zyto lathe, which suites my requirements to a tee. Apart from one.

All the lathes that I used long ago moved the saddle and apron towards the tailstock, when I manually turned the the hand wheel on the apron clockwise.

However when I turn the hand wheel clockwise on the Zyto, it moves the saddle towards the headstock, which I'm finding counter intuitive.

The hand wheel is is connected directly to the bottom of a rack mounted along the side of the bed. The movement of the hand wheel pinion works perfectly whilst operating along the top of the rack (when both have been removed from the lathe).

My problem is that I cannot mount the rack upside down on the bed, as the pinon will jam between it and the bed of the lathe. The pinion is has no gearing between it and the handwheel.

I know that this fault is mine and that I cannot see the wood for the trees, because Zyto would not have produced a lathe that is wildly different from all others at the time.

Can anyone help this befuddled old codger?

Best wishes to you all, John

Hello John,

A common problem with Zyto and old Myford lathes up to and including ML4 as well as Winfields and other clones.. They were all built to a price which meant direct engagement of traverse pinion which gives the carriage movement you are experiencing.

If and only if you can see a way of getting an intermediate gear engaged between these two will you fix that; otherwise it is a case of getting used to it and being careful with working near the chuck.

Regards Brian

Hello John

As Brian says a common problem with some of these older machines, i had the same with a Drummond M type, there are drawings available on the old Drummond Yahoo group of modifications to interpose an idler gear, which may give food for thought. There was a post on this forum by David George about machining and fitting an idler gear to his Drummond, a search here should work. I believe castings are available for that machine, but again thismight give you a few ideas. I had to modify mine as I used a traditional lathe at work and couldn't get used to the change when using my lathe at home, the mod's David did were much more elegant than mine.

Dave

Hi John this is the mod I did on my M Type lathe saddle. I had a casting from Geoff Walker which allows you to add an idle gear to make the handwheel to rotate in the corect direction to saddle direction. I had a few close shaves before the mod.

If you want any info just ask.

David

Dear Brian, Dave and David,

Very many thanks for replying so rapidly, with ideas that actually awakened the one brain cell I have! David I know what you mean when you talk of close shaves. I have an essential tremor, which means that I have had to take great care, as the tool approaches the chuck. The stress is so great, that I use the "sweat of fear" dripping from my forehead, as a cutting lube.

Seriously though, as I do not have access to a friendly proper engineer, I'm not able to use your super adaptations. However the sheer terror of having to use my lathe without resort to your solutions, must have awoken my single brain cell. This led to the following idea, which I would be grateful if you would post comments/suggestions on.

If the pinion runs correctly along the top of the rack, why not flip the rack over, so that its teeth point upwards and mount it lower it on the bed of the lathe? With careful measuring, drilling and tapping the bed and by using shims to keep the back of the rack level with the flats on the bed that it was bolted to, the rack and pinion should engage as required.?? I've checked and there is plenty of room to mount the rack, with its teeth pointing up, instead of down. My worry is that if this is a solution, why did the manufacturer not use it?

Best wishes, John

That remounting of the rack suggestion seems a good idea, but as the teeth will tend to accumulate all the falling swarf, some thoughts on how to shield it would be needed prior to cutting metal.

 There is a picture of a Super Zyto in lathes UK showing an inverted rack:

http://www.lathes.co.uk/zyto/index.html

Edited By old mart on 10/04/2022 18:49:01

Many thanks. I had not thought of that possibility. It will mean though that I'll now have to go out and buy cutting lube fluid, if my idea works!

Best wishes, John.

If you have the space to get the mod in John, and there would seem to be enough as it has been done already and allow for suitable guarding, that is rather a neat solution. I wish you well with it

Regards Brian

It isn't a problem or a fault. it's just the way that it is.

I strongly suspect that direct engagement was used long before an indirect gear train was used.

Basically, if it's your only lathe then the best thing to do is to get used to it.

The inverted rack is brilliant in its simplicity! Other alternatives in the meantime include using a handwheel on the right-hand end of the leadscrew to feed the carriage along. And / or fit a carriage stop so you cant move the carriage close enough to hit the chuck.

Edited By Hopper on 10/04/2022 23:04:48

Hi John if there is enough room to get a 3mm plate between the saddle and rack you could mount the rack on a plate and with slotted holes in the plate adjust it to match the gear and rack engagement. Just a thought.

David

This id a mod I made to my Grayson lathe it could also be done on the Zyto by using parts from an old hand drill

Does seem a feature of older lathes. Mostly cost-cutting and partly because the machine was designed before ergonomics were realised to be important. And sold when hobbyists were pleased to have any sort of working lathe.

Picture below is of a Lincoln Miller, and the first milling machine to be sold in large quantities, circa 1860. Although it did the job, it can't be said to be operator friendly!

I'd learn to live with a Zyto - the feature isn't a show-stopper!

Ergonomics is an interesting subject. Although machine-tool designers sniffed around the subject, it wasn't until customers started complaining about products like sewing machines and motor-cars that anyone took much notice. The military were keen on ergonomics and the subject really took off with radios and radar. A communications receiver has many controls, and receivers are difficult to operate unless they're not laid out sensibly, backlash is eliminated, and the tuning feels good.

Can't expect too much of Zyto vintage machines. They pre-date a number of improvements made during WW2 and after. Better ergonomics are one reason why post-war Myfords were, and are, popular. Doesn't mean Zytos in good condition are junk, they're just less slick than modern designs.

Dave

Edited By SillyOldDuffer on 11/04/2022 10:29:22

The feature is, as said, the handwheel pinion engaging directly with the rack.

Later machines have an Idler gear in the train, so that the Saddle movement is as expected.

Older lathes do have some strange quirks.

The Myford ML4 Leadscrew is right hand thread, so that a power feed towards the Headstock requires two Idlers, in the train, where we would normally expect only one.

It is just a feature with which you learn to live, in the same way that some machines have the Saddle traverse handwheel on the Headstock end of the Saddle, while others have it on the Tailstock end. You just become accustomed to that machine.

Can cause problem when there are two machines with opposite features, and memory lapses, though!

(The Guy Arab 5 bus had a conventional gearchange pattern. The preceding Arab 4 had a mirror image; as did the GS used by Green Line. Being unsynchronised,, you had to know which you were driving! )

Howard

Dear All,

Very many thanks for all your encouraging and helpful suggestions. Each one livened up my day, increased my knowledge and spurred me on to think further about the subject.

Here is what I intend to do and why. First the why.

I'm in the process of moving house, after 38 years, so am rather busy rationalizing my workshops and most of my tools are packed.. Secondly I wish to get the new workshops up and running, before I will feel confident enough to tackle David's idea of a 3mm slotted back plate on which to mount the rack.

My intention is to adopt Hopper's idea and revert the Zyto to its 1920/30's configuration, until I get set up in my new worrkshops. The lathe is in pieces, ready for packing, but I have been able to test the 1920's "adaption" and found that it worked. Because the lathe is small, the ergonomics have not been unduly affected. Once the lathe has been set up and is working, I will post a photo of it in its 1920's configuration, but before that, I shall be avidly reading the posts giving ideas and encouragement, from the experts on this forum.

Very best wishes to all of you helpful engineers,

John

Good stuff John. I am a big fan of the leadscrew handwheel. Much better for feeding than the carriage handwheel. Much steadier and more senstitve and with the graduated dial a previous owner added to my Drummond M-type, it is accurate to the thou. So much so that I added one to my ML7. But it really needs the M-Type leadscrew dog clutch to take full advantage of it. So that is on my Round Tuit list.

I did take a look at my Drummond M-type rack in the shed today and the top of the rack is absolutely littered with swarf, as it sticks out past the bed way and swarf lands right there. The ML7 by contrast has the rack mounted up higher and tucked in underneath the front shear, so no swarf lands there. Could be something to look at on your Zyto before inverting the rack.

I use the lead screw handwheel for all manual feeding on my Zyto. The rack handwheel is far too aggressive and lacks the ability to be precise.

I would say this is the least annoying problem, way down the list after :

1) change gears take ages to reconfigure (often 1/2 hr plus of swearing and getting covered in oil)

2) cross slide and compound handwheels clashing (got around this by turning the compound to face the other way entirely)

3) not a great selection of rpms (on mine anyway)

4) no carriage lock

etc.

other than that it’s a nice little lathe once it’s been set up properly.

Steve

I have an old hand-crank gearbox of an old sewing machine like the one below, that I plan to one day add to the apron of the M-Type as a handwheel reduction gear and rotation reverser. They seem to be common and cheap to buy. It;s just two gears in a housing, one large one small. Perfect, with a little fettling to fit the existing gear and spindle and hand wheel.

I'm still confused by people's desire to have only anti clockwise to move towards the headstock.

Think:- Cross slide is clockwise to move in, top slide is clockwise to move towards the headstock. Why shouldn't the carriage be the same?

Habit from using other lathes.